Grünewald, Stephanie

AbstractNiemann‐Pick disease type C (NPC) is a rare, genetic, progressive neurodegenerative disorder with high unmet medical need. We investigated the safety and efficacy of arimoclomol, which amplifies the heat shock response to target NPC protein misfolding and improve lysosomal function, in patients with NPC. In a 12‐month, prospective, randomised, double‐blind, placebo‐controlled, phase 2/3 trial (ClinicalTrials.gov identifier: NCT02612129), patients (2‐18 years) were randomised 2:1 to arimoclomol:placebo, stratified by miglustat use. Routine clinical care was maintained. Arimoclomol was administered orally three times daily. The primary endpoint was change in 5‐domain NPC Clinical Severity Scale (NPCCSS) score from baseline to 12 months. Fifty patients enrolled; 42 completed. At month 12, the mean progression from baseline in the 5‐domain NPCCSS was 0.76 with arimoclomol vs 2.15 with placebo. A statistically significant treatment difference in favour of arimoclomol of −1.40 (95% confidence interval: −2.76, −0.03; P = .046) was observed, corresponding to a 65% reduction in annual disease progression. In the prespecified subgroup of patients receiving miglustat as routine care, arimoclomol resulted in stabilisation of disease severity over 12 months with a treatment difference of −2.06 in favour of arimoclomol (P = .006). Adverse events occurred in 30/34 patients (88.2%) receiving arimoclomol and 12/16 (75.0%) receiving placebo. Fewer patients had serious adverse events with arimoclomol (5/34, 14.7%) vs placebo (5/16, 31.3%). Treatment‐related serious adverse events (n = 2) included urticaria and angioedema. Arimoclomol provided a significant and clinically meaningful treatment effect in NPC and was well tolerated.

Abstract BackgroundNiemann–Pick disease type C (NPC) is a rare, progressive, neurodegenerative disease associated with neurovisceral manifestations resulting from lysosomal dysfunction and aberrant lipid accumulation. A multicentre, prospective observational study (ClinicalTrials.gov ID:NCT02435030) of individuals with genetically confirmed NPC1 or NPC2 receiving routine clinical care was conducted, to prospectively characterize and measure NPC disease progression and to investigate potential NPC-related biomarkers versus healthy individuals. Progression was measured using the abbreviated 5-domain NPC Clinical Severity Scale (NPCCSS), 17-domain NPCCSS and NPC clinical database (NPC-cdb) score. Cholesterol esterification and heat shock protein 70 (HSP70) levels were assessed from peripheral blood mononuclear cells (PBMCs), cholestane-3β,5α-,6β-triol (cholestane-triol) from serum, and unesterified cholesterol from both PBMCs and skin biopsy samples. The inter- and intra-rater reliability of the 5-domain NPCCSS was assessed by 13 expert clinicians’ rating of four participants via video recordings, repeated after ≥3 weeks. Intraclass correlation coefficients (ICCs) were calculated.ResultsOf the 36 individuals with NPC (2–18 years) enrolled, 31 (86.1%) completed the 6–14-month observation period; 30/36 (83.3%) were receiving miglustat as part of routine clinical care. A mean (±SD) increase in 5-domain NPCCSS scores of 1.4 (±2.9) was observed, corresponding to an annualized progression rate of 1.5. On the 17-domain NPCCSS, a mean (±SD) progression of 2.7 (±4.0) was reported. Compared with healthy individuals, the NPC population had significantly lower levels of cholesterol esterification (p<0.0001), HSP70 (p<0.0001) and skin unesterified cholesterol (p=0.0006). Cholestane-triol levels were significantly higher in individuals with NPC versus healthy individuals (p=0.008) and correlated with the 5-domain NPCCSS (Spearman’s correlation coefficient=0.265, p=0.0411). The 5-domain NPCCSS showed high ICC agreement in inter-rater reliability (ICC=0.995) and intra-rater reliability (ICC=0.937). ConclusionsProgression rates observed were consistent with other reports on disease progression in NPC. The 5-domain NPCCSS reliability study supports its use as an abbreviated alternative to the 17-domain NPCCSS that focuses on the most relevant domains of the disease. The data support the use of cholestane-triol as a disease monitoring biomarker and the novel methods of measuring unesterified cholesterol could be applicable to support NPC diagnosis. Levels of HSP70 in individuals with NPC were significantly decreased compared with healthy individuals.

Abstract Asparagine‐linked glycosylation 13 homolog ( ALG13 ) encodes a nonredundant, highly conserved, X‐linked uridine diphosphate (UDP)‐ N ‐acetylglucosaminyltransferase required for the synthesis of lipid linked oligosaccharide precursor and proper N‐linked glycosylation. De novo variants in ALG13 underlie a form of early infantile epileptic encephalopathy known as EIEE36, but given its essential role in glycosylation, it is also considered a congenital disorder of glycosylation (CDG), ALG13‐CDG. Twenty‐four previously reported ALG13‐CDG cases had de novo variants, but surprisingly, unlike most forms of CDG, ALG13‐CDG did not show the anticipated glycosylation defects, typically detected by altered transferrin glycosylation. Structural homology modeling of two recurrent de novo variants, p.A81T and p.N107S, suggests both are likely to impact the function of ALG13. Using a corresponding ALG13‐deficient yeast strain, we show that expressing yeast ALG13 with either of the highly conserved hotspot variants rescues the observed growth defect, but not its glycosylation abnormality. We present molecular and clinical data on 29 previously unreported individuals with de novo variants in ALG13 . This more than doubles the number of known cases. A key finding is that a vast majority of the individuals presents with West syndrome, a feature shared with other CDG types. Among these, the initial epileptic spasms best responded to adrenocorticotropic hormone or prednisolone, while clobazam and felbamate showed promise for continued epilepsy treatment. A ketogenic diet seems to play an important role in the treatment of these individuals.

Abstract Phosphoglucomutase 1 (PGM1) deficiency is a rare genetic disorder that affects glycogen metabolism, glycolysis, and protein glycosylation. Previously known as GSD XIV, it was recently reclassified as a congenital disorder of glycosylation, PGM1‐CDG. PGM1‐CDG usually manifests as a multisystem disease. Most patients present as infants with cleft palate, liver function abnormalities and hypoglycemia, but some patients present in adulthood with isolated muscle involvement. Some patients develop life‐threatening cardiomyopathy. Unlike most other CDG, PGM1‐CDG has an effective treatment option, d ‐galactose, which has been shown to improve many of the patients' symptoms. Therefore, early diagnosis and initiation of treatment for PGM1‐CDG patients are crucial decisions. In this article, our group of international experts suggests diagnostic, follow‐up, and management guidelines for PGM1‐CDG. These guidelines are based on the best available evidence‐based data and experts' opinions aiming to provide a practical resource for health care providers to facilitate successful diagnosis and optimal management of PGM1‐CDG patients.

Abstract BackgroundNiemann–Pick disease type C (NPC) is a rare, progressive, neurodegenerative disease associated with neurovisceral manifestations resulting from lysosomal dysfunction and aberrant lipid accumulation. A multicentre, prospective observational study (ClinicalTrials.gov ID:NCT02435030) of individuals with genetically confirmed NPC1 or NPC2 receiving routine clinical care was conducted, to prospectively characterize and measure NPC disease progression and to investigate potential NPC-related biomarkers versus healthy individuals. Progression was measured using the abbreviated 5-domain NPC Clinical Severity Scale (NPCCSS), 17-domain NPCCSS and NPC clinical database (NPC-cdb) score. Cholesterol esterification and heat shock protein 70 (HSP70) levels were assessed from peripheral blood mononuclear cells (PBMCs), cholestane-3β,5α-,6β-triol (cholestane-triol) from serum, and unesterified cholesterol from both PBMCs and skin biopsy samples. The inter- and intra-rater reliability of the 5-domain NPCCSS was assessed by 13 expert clinicians’ rating of four participants via video recordings, repeated after ≥3 weeks. Intraclass correlation coefficients (ICCs) were calculated.ResultsOf the 36 individuals with NPC (2–18 years) enrolled, 31 (86.1%) completed the 6–14-month observation period; 30/36 (83.3%) were receiving miglustat as part of routine clinical care. A mean (±SD) increase in 5-domain NPCCSS scores of 1.4 (±2.9) was observed, corresponding to an annualized progression rate of 1.5. On the 17-domain NPCCSS, a mean (±SD) progression of 2.7 (±4.0) was reported. Compared with healthy individuals, the NPC population had significantly lower levels of cholesterol esterification (p<0.0001), HSP70 (p<0.0001) and skin unesterified cholesterol (p=0.0006). Cholestane-triol levels were significantly higher in individuals with NPC versus healthy individuals (p=0.008) and correlated with the 5-domain NPCCSS (Spearman’s correlation coefficient=0.265, p=0.0411). The 5-domain NPCCSS showed high ICC agreement in inter-rater reliability (ICC=0.995) and intra-rater reliability (ICC=0.937).ConclusionsProgression rates observed were consistent with other reports on disease progression in NPC. The 5-domain NPCCSS reliability study supports its use as an abbreviated alternative to the 17-domain NPCCSS that focuses on the most relevant domains of the disease. The data support the use of cholestane-triol as a disease monitoring biomarker and the novel methods of measuring unesterified cholesterol could be applicable to support NPC diagnosis. Levels of HSP70 in individuals with NPC were significantly decreased compared with healthy individuals.Trial Registration: CT-ORZY-NPC-001: ClincalTrials.gov NCT02435030, Registered 6 May 2015, https://clinicaltrials.gov/ct2/show/NCT02435030; EudraCT 2014-005194-37, Registered 28 April 2015, https://www.clinicaltrialsregister.eu/ctr-search/trial/2014-005194-37/DE. OR-REL-NPC-01: Unregistered.

Abstract Phosphomannomutase 2 (PMM2‐CDG) is the most common congenital disorder of N‐glycosylation and is caused by a deficient PMM2 activity. The clinical presentation and the onset of PMM2‐CDG vary among affected individuals ranging from a severe antenatal presentation with multisystem involvement to mild adulthood presentation limited to minor neurological involvement. Management of affected patients requires a multidisciplinary approach. In this article, a systematic review of the literature on PMM2‐CDG was conducted by a group of international experts in different aspects of CDG. Our managment guidelines were initiated based on the available evidence‐based data and experts' opinions. This guideline mainly addresses the clinical evaluation of each system/organ involved in PMM2‐CDG, and the recommended management approach. It is the first systematic review of current practices in PMM2‐CDG and the first guidelines aiming at establishing a practical approach to the recognition, diagnosis and management of PMM2‐CDG patients.